how to clone multiple items on drag using jquery?

Question

I have two div one is main and another in jquery ui modal/popup, which has jQuery UI Draggable applied with multiple item selection. and I want to do, is click and drag that, and create a clone that is kept in the DOM and not removed when dropped i.e clone of selected items.

$(function() {

    var selectedClass = 'ui-state-highlight',
        clickDelay = 600, lastClick, diffClick; // timestamps

    $("#draggable li")
    .bind('mousedown mouseup', function(e) {
        if (e.type == "mousedown") {
            lastClick = e.timeStamp; // get mousedown time
        } else {
            diffClick = e.timeStamp - lastClick;
            if (diffClick < clickDelay) {
                $(this).toggleClass(selectedClass);
            }
        }
    })
    .draggable({
        revertDuration: 10,
        containment: '.demo',
        start: function(e, ui) {
            ui.helper.addClass(selectedClass);
        },
        stop: function(e, ui) {
            $('.' + selectedClass).css({
                top: 0,
                left: 0
            });
        },
        drag: function(e, ui) {
            $('.' + selectedClass).css({
                top: ui.position.top,
                left: ui.position.left
            });
        }
    });

    $("#droppable, #draggable").sortable().droppable({
        drop: function(e, ui) {
            $('.' + selectedClass).appendTo($(this)).add(ui.draggable)
            .removeClass(selectedClass).css({
                top: 0,
                left: 0
            });
        }
    });

});

its working fine to drag and drop. But I need to clone. I try with following with helper 'clone'. but its create clone on same div (source div) i.e if move little after selection.

$("#droppable, #draggable").sortable().droppable({
        drop: function(e, ui) {
            $('.' + selectedClass).clone().appendTo($(this)).add(ui.draggable)
            .removeClass(selectedClass).css({
                top: 0,
                left: 0
            });
        }
    });

any solution or suggestion?